BOV "pumping air back in"

[emptywallet]

hi guys. i'm new to the modding world so forgive the naiveness.

just converted to 4G93T last week and now planning for all the subsequent mods to do.

as most, if not all, turbo car owners religiously go for a bov immediately, in order to showcase and showoff the fact that the engine is macho and powerful, i met a mechanic who thinks otherwise.

he told me something about "redirecting the excessive air back into the car for better air intake, no need woosh-woosh sound" - in his words... more or less (in chinese).

now if you guys don't mind my frankness, most chinese mechanics are english-literaturely challenged, hence the abundance of indegenious anglo-chinese words in workshops such as "ka-la-ji", "beh-ling", "die-saat" etc. which doesn't really help me in understanding what he is trying to say.

he works for a very well-known workshop (which i will casually forget to mention here hence to protect his privacy) and been modding performance cars for a few years there so he must be making some senses, which means i misintepreted his words.

so guys, please help me with my dilemma here, as i would like to showoff my engine as well for 2 reasons; first, it costs me 3-6 months of living-expenses, and second, i need to elaborate my manhood with what's under my car's hood.

is a blow-off-valve necessary and what exactly is the mechanic trying to explain by "redirecting the excessive air back into the engine"? any ideas?

 

[kennethfong]

empty,

you're new, but u can do a search though, plethora of same discussions are available here in the old threads.

ur 93T is using air flow sensor, it measures how much air going into ur intake manifold, it tells ur ECU how much fuel to be injected to ur injector, but when u dump the air out (Vent to Atmosphere Blow Off Valve), the air fuel mixture is wrong, instead of the air going back to ur intake manifold it goes OUT, so u will have sudden rich burn excessive fuel at that particular time and will suffer jerking while changing gears some to the extent of engine stalls, but yours is an auto, the impact might be slightly lesser.... can try and if u have these problems, either convert your MAF into other air measuring system or change back to ur current stock bypass valve.

please bear in mind it has been a fact that the performance of MAF with a vta bov will slow down ur performance by an average 0.5 second in 400m.

hi guys. i'm new to the modding world so forgive the naiveness.

just converted to 4G93T last week and now planning for all the subsequent mods to do.

as most, if not all, turbo car owners religiously go for a bov immediately, in order to showcase and showoff the fact that the engine is macho and powerful, i met a mechanic who thinks otherwise.

he told me something about "redirecting the excessive air back into the car for better air intake, no need woosh-woosh sound" - in his words... more or less (in chinese).

now if you guys don't mind my frankness, most chinese mechanics are english-literaturely challenged, hence the abundance of indegenious anglo-chinese words in workshops such as "ka-la-ji", "beh-ling", "die-saat" etc. which doesn't really help me in understanding what he is trying to say.

he works for a very well-known workshop (which i will casually forget to mention here hence to protect his privacy) and been modding performance cars for a few years there so he must be making some senses, which means i misintepreted his words.

so guys, please help me with my dilemma here, as i would like to showoff my engine as well for 2 reasons; first, it costs me 3-6 months of living-expenses, and second, i need to elaborate my manhood with what's under my car's hood.

is a blow-off-valve necessary and what exactly is the mechanic trying to explain by "redirecting the excessive air back into the engine"? any ideas?

 

[jinkl]

hmm do search bro, cant always spoon feed
here is the thread in zth
http://www.zerotohundred.com/newforums/tech-forced-induction/1525-venting-bov-to-open-air.html

and there alot more , too lazy to retype 100 times

 

[emptywallet]

ok thanx, so basically it is:

(*SUCCCKKK in deep breath*) by pumping out excessive air, it's creating a vacum in the hose which in turn causes the air intake to fill the void by sucking in more air and then misunderstood by the O2 sensor which will effectively tell the injector to feed more fuel to the engine which by the way is actually not feeding any air since the throttle was released, therefore creating a very rich mixture in my engine as i reopened the throttle again... (*panting*)

am i right? hehe...

yalar guys i understand the frustrating repetitions, but unfortunately I do not even understand my own question to start off with and do not know where to start looking, and there are 4 years worth of threads to be read here (i spent 2 nights reading the first 30 pages and i think my short sightedness has worsened)

anyway, that's why you sifus are here ;-)
the link was uselful, thanks!
don't relax man, many more repeating questions to come! hehe...

 

[kennethfong]

ok thanx, so basically it is:

(*SUCCCKKK in deep breath*) by pumping out excessive air, it's creating a vacum in the hose which in turn causes the air intake to fill the void by sucking in more air and then misunderstood by the O2 sensor which will effectively tell the injector to feed more fuel to the engine which by the way is actually not feeding any air since the throttle was released, therefore creating a very rich mixture in my engine as i reopened the throttle again... (*panting*)

am i right? hehe...



No dear, not quite, ur tumbling every term upside down, there is vacuum upon sudden closure of throttle body but the vacuum does not send signal to ur ECU to inject the best fuel mixture data coz u r running air flow sensor, the air flow sensor is the one sending signal to ur ECU.....take a good look at ur current engine, know where ur air flow sensor is, and once u understand how the air principle goes, u'll know vta bov is bad....also ur O2 sensor does not tell ur injector to feed more fuel, O2 sensor is a narrowband sensor mainly feeding back signal to ur ECU for closed loop mode....

however in auto, as i've said, much lesser effect in performance drop but can't guarantee no engine stalls......